RSC Sustainability
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Preparation of marine-sourced alginate fi bres to produce composite paper from both green and blue carbons
Cite this: RSC Sustainability , 2025, 3 , 599
RM. Muhammad Nur Fauzan, a Kotchaporn Thangunpai,
a Akiko Nakagawa-Izumi, b
Mikio Kajiyama b and Toshiharu Enomae * b
Recent trends in papermaking have led to an increase in the use of alternative resources. Alginate fi bres, derived from marine sourced brown seaweed (blue carbon), o ff er a potential alternative to wood pulp in paper production. The process of obtaining alginate involves pre-treatment, alkaline extraction, precipitation, and puri fi cation. Through successful extraction, alginates were obtained from Laminaria japonica ( L. japonica ) and Sargassum polycystum ( S. polycystum ) with yields ranging from 17.4% to 28.9% and 14.7% to 26.8%, respectively. The molecular mass of the alginates ranged from 0.68 × 10 5 to 2.74 × 10 5 g mol − 1 for L. japonica and from 0.39 × 10 5 to 0.994 × 10 5 g mol − 1 for S. polycystum . Calcium alginate fi bres and wood pulp fi bres were combined to create composites. The results from this study suggest that the composites achieved an optimum tensile index when the samples contained 50% calcium alginate fi bres. Although the results were promising, the tensile index of the paper made exclusively from pulp fi bres remained superior. Furthermore, thermal degradation tests demonstrated improved thermal stability for the composite papers compared to hardwood bleached kraft pulp (HBKP) sheets. In conclusion, a composite prepared from a mixture of calcium alginate and wood pulp fi bres was successfully produced and overall 50% inclusion of calcium alginate fi bres provided an optimum composite.
Received 14th February 2024 Accepted 13th November 2024
DOI: 10.1039/d4su00073k
rsc.li/rscsus
Sustainability spotlight Global warming caused by the emission of carbon dioxide gas and the greenhouse e ff ect (GHG) is the most serious, pressing environmental problem facing people around the world today. To e ffi ciently restrain the emission of carbon dioxide gas (CO 2 ) into the atmosphere, forestation is an e ffi cient way to solidify it as green carbon; however, the land area for green carbon storage is planar and limited, while the capacity of carbon storage of oceans is huge, considering that there are many varieties of aquatic organisms from shallow waters to the deep sea. The oceans are home to a wide variety of aquatic organisms called blue carbon. Then, there is much larger accumulation of carbon in the ocean than on land; therefore, circular utilization of blue carbon in a larger amount is sustainable and more advantageous than green carbon; therefore, the subject of this study focuses on the utilization of brown seaweed as blue carbon.
is global warming which is exacerbated by increasing CO 2 emissions coming from plastic production. Such problems not only disrupt food chains and aquatic ecosystems, but also contribute to global warming. Therefore, the replacement of petroleum-based plastics with biodegradable plastic and paper needs to be accelerated. Advanced biomaterial-based innovations seem to ensure sustainability and address waste disposal problems. However, raw bio-based materials, such as polysaccharides and proteins, are mainly harvested from agricultural plants, which may pose a potential threat to the stability of the food supply. 2 Currently, seaweeds and microalgae are gaining increasing attention as promising potential resources because of their high growth rate and extensive environmental tolerance, signi cantly alleviating the competition between food and water resources. 3,4 An algi- nate is a polysaccharide that exists mostly in the cellular wall
1. Introduction Since their invention, plastics have become an important material in our daily lives. However, decades of accumulation of plastic have resulted in signi cant environmental problems due to their innumerable uses. More than 10 million tons of plastic waste end up in the oceans annually and more than 80% of the marine litter is plastic. 1 Some plastic wastes, such as disposable plastic containers and plastic bags, end up in the marine environment, leading to the accumulation of microplastics that are further subdivided and oat. Additionally, a pressing issue
a Degree Programs in Life and Earth Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan. E-mail: enomae.toshiharu.fw@u.tsukuba.ac.jp b Institute of Life and Environmental Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8572, Japan
RSC Sustainability , 2025, 3 , 599 – 610 | 599
© 2025 The Author(s). Published by the Royal Society of Chemistry
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